1. Field of the Invention
The present invention relates to a soundproofing cover, which can inhibit noises from generating by absorbing noises produced by an engine of an automobile, and the like.
2. Description of the Related Art
In recent automobiles, an engine cover is disposed in order to seal the noises, which are produced by the engine, and to upgrade the fine appearance in the engine room. This engine cover, for example, as disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 10-205,352, is constituted by a hard sound sealing layer, which is composed of a resin or steel plate, and sound absorbing layer, which is laminated on an engine-side surface of the sound sealing layer and which is composed of a polymer foamed substance. In the engine cover, the sound sealing layer seals the sounds, which are produced by the engine, and upgrades the exterior appearance. Then, the sound absorbing layer absorbs the sounds, which are produced by the engine.
However, since the sound sealing layer is formed as a hard plate shape, there arises a problem in that the sound sealing layer becomes the generating source of the sounds when the sound sealing layer itself vibrates. Accordingly, the sound absorbing layer inhibits the sound waves from reaching the sound sealing layer and inhibits the sound sealing layer from vibrating. In addition, the engine cover is fastened to an engine or adjacent to the engine by way of a vibration-proofing component member, such as a rubber mount, etc. With such an arrangement, the vibrations of the engine are inhibited from transmitting to the sound sealing layer.
Since the foamed urethane, which has been used widely as the polymer foamed substance, exhibits the independent porosity rate as low as a couple of percentages, it is extremely good in terms of the sound absorbing characteristic. However, the foamed urethane has a problem in that it shows a low sound sealing characteristic. In addition, in order to have the sound sealing layer exhibit a sufficient sound sealing characteristic, it is necessary to give it a large mass of certain extent with respect to a unit surface area of the sound sealing layer. Thus, the weight of the sound sealing layer has enlarged inevitably, and accordingly has resulted in the outcome against the lightweight requirement.
Hence, in Japanese Unexamined Patent Publication (KOKAI) No. 2,000-230,431, there is disclosed a soundproofing cover, which includes a polymer foamed substance with an increased independent porosity rate and whose surface is exposed. In accordance with the thus constructed soundproofing cover, it is possible to coexist the sound absorbing characteristic with the sound sealing characteristic by the polymer foamed substance only. Namely, since the independent porosity rate is high, the transmitting sounds are reduced to exhibit the sound sealing characteristic, the sound sealing layer can be obviated and the lightweighting can be achieved. Moreover, since the sound absorbing layer is exposed, it is possible to absorb the reflective sounds in the engine room. In addition, since the polymer foamed substance is soft, and since its surface is formed as a rough surface having open pores, it does not produce the sounds even if it vibrates.
By the way, when installing a soundproofing cover, like the one which is disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 2,000-230,431, to a mating component member, such as an engine, and so on, it is possible to fasten it by way of a separate component member. However, it is desirable, when forming the polymer foamed substance, to carry out insert molding so that a plurality of brackets protrude from the resulting polymer foamed substance, and to fasten the soundproofing cover to a plurality of portions of the mating component member to be installed to the soundproofing cover by way of a bolt hole, and the like, of the brackets, which project from the polymer foamed substance. With this arrangement, since the entire surface of the polymer foamed substance is exposed, it is possible to inhibit the impairment of the sound sealing characteristic, which is caused by exposing a hard material. Hence, in the technique disclosed in the aforementioned publication, a plurality of brackets are made integral with the polymer foamed substance independently of each other.
However, in the soundproofing cover, the polymer foamed substance is insufficient in terms of the rigidity so that the configuration is not stabilized. Even when the sound proofing cover has high dimensional accuracy, there arises a problem in that the positioning operability is low as it is installed to the mating component member.
Therefore, it is possible to think of connecting all of the brackets. With this arrangement, the rigidity can be secured by the brackets. Accordingly, the positioning operability can be improved by making a soundproofing cover with high dimensional accuracy.
However, it is not always the case that a plurality of the portions of the mating component member to be installed to the soundproofing cover are on an identical mating component member. For instance, there is a case that the soundproofing cover is fastened over an engine body and an intake manifold. In such a case that the portions to be installed to the soundproofing cover are present on a plurality of mating component members, it cannot necessary say that the mutual positioning accuracy between the mating component members is high. There even arises a case that the mutual dimensional accuracy of the respective portions to be installed to the soundproofing cover is low. Hence, even when the soundproofing cover is made highly accurate dimensionally by connecting a plurality of the brackets, there arises a case that the installation operability cannot necessary be high, and that the installation operability may rather be lowered instead. It is rather desirable to make a plurality of the brackets independently of each other and to install the soundproofing cover by partially expanding or contracting the polymer foamed substance. However, due to the lack of the rigidity, it is not possible to improve the problems that it is difficult to carry out the positioning, and that the soundproofing cover is inferior in terms of the installation operability. In addition, since the brackets are usually made of a metal, it is needed to decrease the usage amount as less as possible in order to satisfy the lightweighting requirement.
The present invention has been developed in view of the aforementioned circumstances. It is an object of the present invention, in a soundproofing cover which is free from a hard sound sealing layer, to improve the positioning accuracy in the installation of the soundproofing cover to the portions of a vehicle to be installed thereto, and to satisfy the lightweighting requirement.
A soundproofing cover for a vehicle according to the present invention can carry out the object set forth above. It absorbs noises, which are produced by a vehicle, is fastened to a plurality of portions of the vehicle to be installed to the soundproofing cover, and comprises: a cover body composed of a polymer foamed substance; a plurality of brackets held integrally to the cover body; and the respective brackets having an installation portion to be fastened to the portions of the vehicle to be installed to the soundproofing cover and a holding portion held and fastened integrally to the cover body, and at least two of the installation portions constituting a datum bracket connected by one of the holding portions shared commonly.
Namely, in accordance with the soundproofing cover of the present invention, the positioning accuracy can be improved in the installation of the present soundproofing cover to the portions of the vehicle to be installed thereto so that the installation operability can be upgraded. In addition, the increment of the weight can be kept minimum so that the lightweighting requirement can be satisfied.